Sensor cell structure for oxygen-combustibles gas mixture sensor

Claim 1

A cell structure for an oxygen-combustible gas sensor comprising: a sensor housing; a porous mechanical support member of electrically non-conductive material mounted in said housing and dividing said housing into a first zone in communication with a gas to be measured and a second zone in communication with an oxygen containing gas; an oxygen sensor cell including a first electrode disposed on said porous member; an electrode connection layer in electrical contact with and providing a terminal for said first electrode, said electrode connection layer consisting of an electrically conductive material which does not allow gaseous diffusion therethrough; a thin film layer of solid electrolyte, a portion thereof contacting said electrode connection layer and overlapping said first electrode such that said solid electrolyte in combination with said electrode connection layer seals said first electrode onto said porous member, and a non-catalytic second electrode disposed on said solid electrolyte opposite said first electrode; and a combustibles sensor cell including a first electrode disposed on said porous member, an electrical connection layer in electrical contact with and providing a terminal for said first electrode, said electrode connection layer consisting of an electrically conductive material which does not allow gaseous diffusion therethrough, a further portion of said thin film of solid electrolyte contacting said combustibles sensor electrode connection layer and overlapping said combustibles sensor first electrode such that said solid electrolyte in combination with said combustibles sensor electrode connection layer seals said combustibles sensor first electrode onto said porous member, and a catalytic second electrode disposed on said solid electrolyte opposite said first electrode; said solid electrolyte and both said electrode connecting layers effectively seal said porous mechanical support member substantially isolating said first zone from said second zone; whereby both said first electrode of said oxygen sensor cell and said first electrode of said combustibles sensor cell are in communications with the reference gas through said porous support while said non-catalytic second electrode of said oxygen sensor cell and said other catalytic second electrode of said combustibles sensor cell are in communication with the gas to be measured.